This comes from CT, and is probably one of the most Basic Principles:
“To make long-term improvements, one needs to apply the law of progressive overload, which states that the demands of a training program should become more difficult as the body adapts to training.”
Training to failiure is completly unnecessary. It only burdens you with longer recovery periods.
Diet decides whether you’re getting bigger or not and how much of it is going to be actual muscle. Count what you ate during the day, it’s essential.
For mass, volume and intensity are inseparable - getting them both(heavy weight, high sets, low reps for example) is mandatory!!! Otherwise you’re training for endurance or strength.